The adsorption of CO on Cu (211), serving as model system for the adsorption of CO in stepped surfaces, has been investigated using electron energy loss spectroscopy (EELS). At a surface temperature of 110 K, CO adsorbs nondissociatively and is drawn exclusively to descending step sites in this system. On-top and bridge sites are sequentially populated with the CO axis being perpendicular to the surface. In addition, at low coverage, a molecular state is observed, for which the CO axis is strongly inclined.